Regular undergarments in current use are made of cotton and/or synthetic materials. The cotton and synthetic panties typically do not offer barrier protection. Often the synthetic panties have a cotton lined crotch to absorb vaginal discharges or perspiration. The absorbent/barrier properties of regular undergarments are minimal such that any vaginal discharge and/or heavy perspiration may strike through onto outer clothing (i.e. liquid penetrates from the interior to the exterior of the undergarment.)
Panty liners and feminine care sanitary napkins or pads used with regular undergarments have polyethylene backings that provide some barrier properties inhibiting liquid strike through. However, if the vaginal discharge extends to the sides or the ends of the pads it can leak or seep around an edge of the pad and onto the undergarment. Such leakage can stain the undergarment. Depending upon the amount of leakage, liquid may strike through or go around the undergarment and stain outer clothing and/or bedding. Women with heavy liquid flows may use one or more maxi pads, double pads and/or tampons alone, or in combination, and change these pads and tampons frequently to prevent embarrassing, messy leakage around the edges of the pads and/or staining of outer clothing. In some cases, during their heaviest flow days, some women will restrict their activities and stay home.
Many women experience some leakage of menses from their pads to their undergarments. This varies from being limited to a small number of pads leaking onto only the undergarment during light flow to more prevalent leakage onto the wearer's outer clothing on pads worn during heavy flow. Normally this leakage occurs at the side of the pad, although end leakage is also a problem. Placement of maxi pads and overnight pads in the crotch of regular undergarments shows that, at best, the pads lay on the leg elastic and, at worst, overhand the leg elastics. This causes side leakage onto the undergarment and possibly onto outer clothing. Typical leakage from the pad is caused by poor fit of the pad to the body, improper positioning of the pad by the user and lack of absorbency. Leakage from the undergarment onto the outer clothing is typically due to incompatibility between the pad width and the undergarment crotch width and/or lack of barrier properties in the undergarment material around the edge portion of the pad.